For such a known generic forming tool, a metal workpiece heated to the austenitizing temperature is formed. The forming tool has a cooling device by means of which the workpiece present in the forming tool is quenched in order to convert the austenitic structure to a martensitic structure, i.e., to harden the workpiece. In this regard, it is important to maintain a specific variation of the temperature of the workpiece over time to achieve the desired hardness and type of martensitic structure. In particular, a minimum cooling rate is necessary. On the other hand, the cooling must be coordinated with the forming. If the workpiece hardens too soon, the forming is adversely affected.
The workpiece is held in the forming tool until it has cooled to a temperature of approximately 100° C. This ensures that the workpiece has sufficiently cooled and has dimensions that essentially correspond to its final dimensions.
The workpiece is then delivered to further machining steps in which its outer contour is trimmed, for example using a laser or plasma cutting unit.
JP 2005-248253 A relates to a method for hot forming of steel material. The steel material is heated and positioned between an upper die and a lower die. The hot forming is then performed. The closed dies together with the workpiece present therein are moved downward relative to a punch and a trimming edge in order to punch the workpiece and trim its edge. The punch cooperates with a punch recess in the upper die, and the trimming edge cooperates with a side edge of said die. The punch and the trimming edge are fixed to a stationary platform.
US 2002/0113041 A1 discloses various forming devices. One of these forming devices also has a punching die which is provided in an upper die and cooperates with a corresponding recess in a lower die. A workpiece is placed between the opened dies. The dies are then brought together, thereby forming the workpiece. When the dies are completely brought together they securely hold the workpiece in position, thus allowing punching to be carried out using the punching die.
WO 99/26740 relates to fine-edge blanking of a semi-hot formed workpiece. In a first process area punching material is provided, in a second process area is preheated, and in a third process area is heated to a semi-hot forming temperature and is formed. Fine-edge blanking of the completely formed part is carried out in a fourth process area.
DE 10 2004 019 693 A1 relates to a method in which a workpiece is heated to a temperature of approximately 950° C., and is then hot formed using a first and a second die. After the dies are closed, the workpiece remains for a period of time between the closed dies in order to cool. During the holding period the workpiece is punched, using a punch provided in the lower die.